Management of Nitrogen and Phosphorus in Castor Bean Culture (Atena Editora)

Abstract

The castor bean (Ricinus comunis L.), also known as carrapateira, is demanding in nutrients, presenting good response in productivity to fertilization. Preferably, planting is recommended in well-prepared, fertile, deep and loose soils, to allow the development of the root system. This work aimed to evaluate the response of a cultivar (BRS Energy) and a lineage (CNPA 2009-7) of castor bean to increasing doses of N and P in the soil in two locations in the northeastern semi-arid region: rural areas of the municipalities of Apodi (RN ) and Barbalha (CE). The doses of N tested were: 0, 50, 100, 150 and 200 kg/ha and those of P, 0, 50, 100, 150 and 200 kg/ha. The experiments were distributed in randomized blocks with four replications, making a total of 40 plots. The cv. BRS Energy showed a greater absorption of nitrogen in the soil and, consequently, synthesized more crude protein than the CNPA 2009-7 genotype. In addition, it showed greater efficiency in calcium absorption. On the other hand, the genotype proved to be more efficient in the absorption of phosphorus and magnesium. The cultivar naturally showed a higher castor bean production, as evidenced by the significantly higher variables related to the production of fruits and seeds. It also had a higher oil content in relation to the genotype. In both locations, the content of N and, consequently, of proteins, in castor bean leaves increased as a function of the dose of nitrogen fertilizer.